That sounds a more civilized way of doing things. However Irish Rail have a more confrontational attitude to their passengers.
This system is done in intercity journeys here. They only travel in two's on IC services where they know people can be caught and other than this its just a single checker.
They only target commuter stations in large numbers.
As for fare adjustment, passengers here know the exact fares from the TMV's or ticket offices and it would be abused by people taking chances of paying a shorter fare and hoping for the best not to be caught.